Applicant has previously disclosed and patented a commercially significant improvement upon those prior plastic and metal closures for bottles and containers which are designed to include a tamper-evident feature. In most cases, this tamper-evident feature had comprised a lower shoulder or skirt portion of the closure, which was in some way intended to fracture or break upon removal of the closure from the container, so that it then became evident that the container had been opened. A large number of these closures had been known in the past, including even several which were used on a commercial basis, particularly in connection with carbonated beverage bottles and other such containers maintained under significant pressures. Up until quite recently, metal closures had predominated in this respect. However, applicant's prior invention, as set forth in U.S. Pat. No. 4,343,408, has been quite successful in replacing these prior closures.
In that regard, applicant's patented closure has significantly improved upon these prior closures, particularly in that applicant's device has now permitted the closure to be removed cleanly and efficiently, and to obtain the fracture of the lower skirt portion in a highly reliable manner. Furthermore, applicant has provided a commerical closure which can be applied in a single step to a container or bottle, and one which can at the same time result in highly efficient breaking or fracturing upon closure removal.
Applicant has also patented a further improvement on this closure, which includes juxtaposed parallel intermediate side wall surfaces which help to maintain the upper and lower intermediate side wall portions of these closures in alignment with each other upon collapse of the frangible bridge means as the closures are applied to the containers, and thus more efficiently operate such systems. These improved devices are set forth in U.S. Pat. No. 4,461,390. Again, all of these closures have been highly successful in commercially adapting these closures to these types of containers.
Furthermore, in U.S. Pat. No. 4,479,586 the applicant has set forth yet another improvement in these closures, in this case relating to the inclusion of means for insuring that the portion of the closure which remains on the container after the closure has been removed now separates from the upper portion of the container so as to visibly reveal fracture thereof. In this patent, this is accomplished by including an inwardly directed non-locking tapered surface on the container itself so that when the closure fractures the depending lower skirt portion is caused to move downwardly along the non-locking tapered surface away from the annular collar portion of the contained to provide such visual evidence.
While all of these closures and containers have provided commercial products which can not only provide the tamper-evident function, but which can also visibly demonstrate same, the search has nonetheless continued for even greater improvements in these devices, and most particularly to provide a structure which is fool-proof in connection with highly repetitious operations. It must be recognized in this regard that in applying these closures to bottles or other containers many hundreds of thousands of applications are carried out repetitiously. It is nevertheless important that each such application result in the clean and uniform application of the closure to the container, without prematurely fracturing the bridges on the closure, and in a manner such that when the closure is subsequently removed these bridges will then cleanly and uniformly fracture with relative ease. Thus, even if only a few percent of the closures thus applied do not perfectly meet these requirements, in many situations this will not be an acceptable result in the particular commercial operation involved.